Acetylated tunicate nanocellulose-based high-efficient air filter media with antibacterial property

Abstract

Nanocellulose has great potential for application in highly efficient filter media. However, its application is hindered significantly by the structure collapse of nanofiber networks due to capillary adhesion and hydrogen bonds formed during the wet-laid process. Here, the tunicate nanocelluloses (TNCs) are modified with acetic anhydride and (3-Aminopropyl) triethoxysilane, respectively, to alleviate such collapse of the nanofiber networks. The obtained acetylated tunicate nanocelluloses (ANCs) and silylated tunicate nanocelluloses (SNCs) are applied to fabricate composite filter media together with a glass fiber (GF) substrate layer. The filtration efficiency of TNC/GF, ANC/GF, and SNC/GF filter media increase to 99.983%, 99.991%, and 99.994%, respectively, compared with pure glass fibers filter media (99.916%). The smaller air resistance of ANC/GF filter media (314.3 Pa) compared to that of TNC/GF (323.9 Pa) and SNC/GF (346.7 Pa) filter media contributes to a larger quality factor (0.03 Pa-1). The ANC/GF filter media shows antibacterial capability. The survival rate of escherichia coli (E. coli) and staphylococcus aureus (S. aureus) bacteria with an original concentration of 2✕107 cell/mL decreased to 44.2% and 5.8%, respectively, after exposure to ANC/GF filter media for 6 h. Their survival rate decreased to less than 0.5% after exposure to the ANC/GF filter media loaded with silver nanoparticles for 1 h. This work will promote the application of nanocellulose in highly efficient air filter media.